The present invention is a process of the preparation of hydrolyzable .beta.-cyanoalkylsilanes. More particularly, this invention relates to the catalytic addition of silicon hydrides to .alpha., .beta.-unsaturated olefinic nitriles to form .beta.-cyanoalkylsilanes. The instant process employs novel catalysts comprising a diamine and non-activated copper or a copper containing compound.
Hydrolyzable .beta.-cyanoalkylsilanes are useful for the production of polyorganoxiloxanes containing the .beta.-cyanoalkyl substituent. The silicon-bonded .beta.-cyanoalkyl radical is extremely resistant to hydrolysis and cleavage under hot, humid conditions. Therefore, the .beta.-cyanoalkylsilanes find particular use in the preparation of polyorganosiloxanes which must be subjected to hot humid conditions. The presence of the silicon-bonded .beta.-cyanoalkyl radical substituted on polyorganosiloxanes also tends to stabilize the polyorganosiloxanes against swelling induced by liquid hydrocarbons.
Bluestein, U.S. Pat. No. 2,971,970, issued Feb. 14, 1961. describes a method for forming cyanoalkylsilanes. The method comprises reacting a hydrolyzable silicon hydride with an .alpha.,.beta.-unsaturated olefinic nitrile in the presence of a diamine and a cuprous compound selected from the class consisting of cuprous oxide and cuprous halides.
Rajkumar et al.. Organometallics 8, 550-552, 1989, describes a two-component catalyst, consisting of cuprous oxide and tetramethylethylenediamine, that promotes .beta.-hydrosilylation of acrylonitrile.
Svoboda et al.. Collection Czechoslov. Chem. Commun. 38, 3834-3836, 1973, describes binary systems of a copper compound (Cu(I) oxide. Cu(I) chloride, and Cu(II) acetylacetonate) and an isocyanide (tert-butyl or cyclohexyl isocyanide) as effective catalysts for hydrosilylation of acrylonitrile by trichlorosilane and methyldichlorosilane.
The present process employs novel catalysts, comprising a diamine and non-activated copper or selected classes of copper compounds, which promote the .beta.-hydrosilylation of unsaturated olefinic nitriles by silicon hydrides.